Method of and apparatus for selecting fiber



Dec. 30, 1930., v R. A. WEBBER 7 Inn-non or AND APPARATUS rfoa ssnacnue mssa Filed July 18, 192'! 7' Sheets- Sheet 1.

Dec, 3%, 393%. 'R. A. WEBBER J 5 METHOD OF AND APPARATUS FOR SELECTING FIBER Filed July 18, 1927 7 Sheets -Sheet 2 Dec. 30, 1930,

R. A. WEBBEB 1,786,973

METHOD OF AND APPARATUS FOR SELECTING FIBER Filed July 18, 1927 7 Sheets-Sheet s Dec. 30, 1930. R. A. WEBBER 73 METHOD OF AND APPARATUS FOR SELECTING FIBER Filed July 18, 1927 I 7 Sheets-Sheet 4 PPM/4%? fE l/wd m W1 Dec. 30, 1930. R. A. WEBBER METHOD OF- AND APPARATUS FOR SELECTING FIBER Filed July 18, 1927 7 Sheets-Sheet 5 WiK/ X205 f z' i Dec. 30, 1930. R A. WEBBER 1,786,973

METHOD OF AND APPARATUS FOR SELECTING FIBER Filed July 18, 1927 7 Sheets-Sheet 6 7 Sheets-Sheet 7 Filed July 18, 1927 30mm 4. WEEBEE, or 3mm, iNEw'naursHmE, assien'on are contrar E BERLIN, NEW nmrsnmn, A coaromzrron or MAINE.

. I METHOD OF AND APPARATUS FOR SELECTING FIBER Application filed July 18,

Cellulose fiber as found in nature or pulp liberated from Various ,cellulosic, materials such as wood, consists of fiber units of widely varying lengths, some being below and some above a certain average fiber length possessed 3 ing members or edges capable of picking up the long fibers, and then removing an recovering the picked fibe'rs. Either the edges may be moved through the pulp,

pulp lnoved past the edges but, owin to the fact that the second method involves t e handling of very lar e volumes of suspended pulp, the prefera le method .is one, which involves, .movmg the edges tlirough the pulp as thispermits more economical commercia operation. a f 1 When edges are moved through a. suspendedpulp, the long fibers are caught or picked up by being folded, over the edges, and

the small'fibers or fiber fragments slip by.

In actual practice, the mechanism of selection is doubtless quite complex.- It is thought that probably the edge picks up a layer of fibers upon first entering the stock, and as it moves therethrough =continues to pick up more fibers until anaccumulation of fibers s produced which after awhile itself consti tu-tes the edge. As the accumulati n grow's,

- fiber selectivelydoubtless varies, an entrainment aswell as selection takes; place.

. A method such as described-may be used with great advantage, as it is capable of yielding, a product ofmaterially higher fiber length having certain characteristics notably superior. to those of the original pulp; For.

exa'mple,,the' selected fiber will produce a. strong r; and more isitiiibl paper. ofgreate'rj teai'ing resistance an 7 I Itffis whiter, cleaner, Land more absorptive H folding endurance.

the ilitb "cree .1 .1 12 nd; ire-see a:

or the i 1927. Serial m zoes'm higher total and resistant cellulose content and a lower co per number, these improved characteristics doubtless resultmg from its segregation from the color-' ing, colloidal and other im urities usually presentwith the short'apd roken fibers of the orlginal pulp. When selected from wood pulp which has been refined to high al ha cellulose content, it is eminently suita 1e. for the manufacture of high grade papers, such as fine writing, bond, and ledger, for sheetnng into-absorptive webs to. be used asthe base for the manufacture of impregnated products such as artificial leather, and for the preparationof high grade cellulose derivatlves. I

Various types of selectorswill be described, but each type involves the use of multiple edges, which may take the form'of blades or wines. dimensioned so as to be. capable of picking up orselecting long fibers when moved through a pulp or fiber suspension.

The fibers may then .be removed from the ed es as by shaking or by spray-washing, the latter method being preferable, as "prac- 'tically. all the fiber may thus be recovered."

Where wires are employed as the edge-presenting members, they are preferably of noncircular cross-section, for instance, u'are or conveniently arranged in the form ,of a grille.

I With these and other features in view, my invention consists in'the method, as well as the construction, combination and arrangeinent ofparts hereinafter described in ,conjunction with the accompanying drawings,

wherein I Figure 1 illustrates inperspe'ct'iveaiselector ofthehand-type': 1 p

E'gure 2rshows a similar; viewofa Somewhat different type ofhand-'selector.

5 Figure?) represents diagrammaicallyfa selector of the reciprocating typeandhaving only one selectorgiiille triangularychiefly, because fiber wlll turn' Figure 4'shows in perspective-the selector grille.

1 Figure 5 represents in side elevation a preferred selector of the rotor type installed in -a pulp mill. v

Figure 6 shows a detail of fiber formation Y on a shar -edge selector blade.

Figure ?.is a side elevation of a portion of the selector shown in Figure 5, illustrating the mounting of the grilles.

Figure 8 is a section on the line 88 of Figure 7. r I

Figure 9 is a section on the line 99 of rotor selector.

I Figure 12 shows in perspective the rotor with but one grille attached.

Figure 13 represents a sectional view of still another type of rotor selector.

Figure H is a side elevation of the same.

Figure 15 illustrates in perspective another type of selector.

Referring tothe drawings, Figure 1 represents one form of hand-grille or selector made'up ofstrips 1 of copper or other sheet metalarranged in spaced parallel relationship and soldered at their ends to similar cross-strips 2. The edges of the strips may be either relatively sharp or else left blunt, as shown, and may correspond to a. thickness of about 3 inch. The grille may be provided at its endswith arch-shaped pieces 3 tied together by .a cross-piece 4, serving as a handle. In operation, the grille is lowered into the pulp to be subjected to selection, and

then quickly drawn up. The. grille may then be transferred to a fiber-recovery vat wherein the selected fibers may bethoroughly washed therefrom While held in an edgewrse position. I In Figure 2 is shown a handgrllleconsisting'of blades 5 arranged both lengthwise and crosswise. Because of its greater edge length, this type of grille gives a greater yield of fiber per unit of area per d1 than that shown in Figure 1.

: and-type selectors, such as described find utihty in the laboratory, giving sufliclentyield of selected fiber for such purposes. For obtaining larger yields of selected fiber, it isnecessary to provide apparatus capable of selecting fiber automatically. Figure 3 illustrates diagrammatically an apparatus of this type, comprising only one selector grille and intended to reproduce mechanically the operations ofshand-selection. As shown, the pulp-to be subjected to selection is maintained in a tankfi into and out of which swings a grille 'Igfixed to the lower end of an arm '8. The armisfixed at its upper end to a rock shaftt which causes the grille to move to and fro in anarcuate path through the pulp, and to strike abruptly against stops 10 at both ends of its path and thus cause the wet fibrages to be shed from the grille into collecting troughs 11. While apparatus of this type requires no spray wator. for the recovery of the selected fiber, the yield is, low for economical commercial operation, because only a single grille moves through the-stock at a given time,-and a cer-' tain amount of motion is lost at the end of each movement. 1

A selector which gives good yields is one consisting of a rotor or other endless carrier on which is mounted an endless succession of grilles, the number of grilles moving through the pulp at a given time being as high as possible. In Figure 5, a preferred selectorof this type is shown installed in a pulp mill, and intended to operate upon pulp just as it comes from a riflling or screening mechanism, the pulp thus being 'in an unbeaten or comparatively freecondition. As shown in this figure, the pulp flows from a box 15 into a sup ly channel 16, and thence through grating 1? past a gate 18 into a vat 19 in which a selector unit 20 operates. The selector rotates in the same direction as the pulp flows and picks up mainly the long fibers, these being removed therefrom by water jets from a water pipe 23, and, falling into a collecting trough 24, gravitate into an outlet spout 25. The rest of the pulp flows over a dam21, and, if desired, also over an inclined screen 220i fine-meshed wire or perforated plate, through the openings of which the fibrillae or fiber fragments and fine impurities pass, the short fiber discharging into 7 a tank 26, and the fines together with the associated white water into a spout 27. v

The selector unit comprises spaced spiders '29. fixed to a shaft30, on which the selector grilles are mounted. Each grille, as best shown in Figure 8, comprises a plurality of blades 32, mounted on a rod 31, preferably of square section, so that the blades are incapable ofturning there( 11. The blades are maintained fixed in spaced relationship by spacers 33. Each rod is attached, near its end to one of the spiders, by an eye-bolt 35 whose shank passesthrough a slot 37 in the rim of the spider. The rod is threaded at each end for the reception of a nut 36 serving to maintain the spacers and blades in as sembled condition.

The grille is assembled with a spider by passing the eye-bolt throiigh the slot 37 formed in the rim 38 and screwing, on the threaded end of the bolt a nut 39 which clamps the rod againstthe rim. The rimis. shown as grooved at 40 near the opening for the reception of the spacers 41 adjacent to the eye-bolt. Grilles are thus assembled in the desired spaced relationship about the en-- tire periphery of the spiders. The blades 32 of a somewhat different type, employing wire grilles and -equipped with internal spray heads'or nozzles. The selector comprises a pair of spaced discs 48, bridged by grilles 49 of coarse mesh wire secured to their inner faces at an angle somewhat in advance of radiallines passing through their outer ends.

The discs are mounted for rotation on a hol-. low shaft 50. A' series'of nozzles 51 impinge jets of water against the grilles'when" they have rotatedfout' of a vat 55 in which-the. selector is mounted to operate. A gland (not shown) may be clamped about the shaft in such way as to permit the shaft to rotate within it, the gland being held in a stationary position as by a weighted arm.- To the gland maybe attached the nozzle or series of nozzles 51,.supplied with water from the hollow shaft which turns in the-gland. The selected fiber picked upby the blades 91' wires is Washed into a collectin trough 52, leaving through adischarge pipe 53. The stock 0 be subjected to selection is fed into the vat from a supply pipe 56, flowing in the'directionof the peripheral movement of the. selector, and, after being acted upon by the- -sel.ector,leaves through an outlet pipe 54;

Figures- 13 and 14. illustrate still another form of rotor selector. One end of the ro- ,t or-'consists of a disc 58 rigidly affixed to and supported by a shaft 5 9 by which rotation of the selector as a whole may be effected. The other end consists of'a. ring 60, revolving over a series of rollers 61 moun'ted on a stationarychannel ring .62 supported in any suitable manner. A series of rods 63 bridging the ring and thedisc 58 serve 50' to support. rows of radial selectorblades 64 of-the grilles,-as

' in spaced relationship. The rotor-operates 'in a vatl 65 supplied with pulp from an in-' let pipe66, the pulp flowing in the direction I of rotation of the rotor and leaving through 5; an outlet pipe 67. The blades 64 carry the picked-up or selected fiber until a series of water jets emitted radially from a pipe 68 'Wash-the fibers therefrom into acollecting trough 6.9, from which ethe selected pulp so passes through adischarge pipe 70.

' Another type of selector is that shown i11 F1gure 15, wherein e dless beltsare en1-- proceeds, the pulp density in the unselected -is shown operating in an inclined tank 71 selector structure therein. "The tank at its lower end a trough 72 wherein the.

fiber selection takes place, and at its upper. end a trough portionv 73 wherein the selected fiber is washed offand collected. The stock is fed from an inlet pipe-74 into thelower g trough portion 72. Spaced endlessbelts75 grilles 76 comprising aplurality of p .77 arranged in spaced parallel rela carry blades tionship through thetanlg.

Rolls 78 and 79, respecti upper and lower troughs, serve to gu' e the vely located in the j belts, either roll beingdriven to ca se the movement of the grilles, through the tank. rilles pass through thepu-lp in the,

As the trough 72, they pick up the long fibers, and

then carry them around the roll 79 and thence upto the trough 78, where a series of sprays from a water pipe 80 impinge thereagainst to ,wash theselected fibers into the trough 73 from which they pass through an outlet pipe 81, The unselected short fiber combined with good yield isdesired. This is due to the fact'that the speed ot a bluntedge member through the pulp must be relatively quite'low in order-to avoidpushing the stock as a whole aheadmfleac-h member and thus lower the relative motion of grille and pulp. At low relative speeds of grille and stock, the 'selectivityflis less than at the highrelative' speeds at which sharp-blade 'rilles'may be moved through the pulp. I But 1f high selectivity is not desired. that is. if the selected pulp is to be of on lv slightly higher average fiber length, the blunt-edge selector may be desirable because of the diighe ryield obtainable. l While selectors of the capable of operatingon stocks at various densities, .it,.is generally preferable'to have 31 density of below 1%, say about .2% to..3%.

asunder these conditions both-the yield and:

selectivity are good. The pulp is preferably fed inthe same direction as the movement otherwise considerable resistance is offered against the grilles. Butthe pulp type described are flow should be slow, since otherwise'little fiber would be picked up, as rela tive motion is 'necessary. 4 While. it, is pos-.

sible to. subject the same pulp to selecting action anumber of times, this is generally unnecessary 'in'actual practice, for with a properly designed selector it has been found possible to remove a large proportion, say 50%,pf the long fiber, passing it through a single selecting mechanism. .As selection .stock' gradually decreases froman initial value of, say, 0.3% to 0.2%. Asthis takes 65 shown partly broken away to disclose the place, the fiber yield drops, this drop being especially rapid when the density falls below 0.2%. If desired, however, pulp may be subjected to' several selections to produce several different grades of selected fiber. Thus. about 50% to 60% of the pulp may be selected into one grade, then 20% to 30% of the remaining fiber into another grade,

the fiber being thickened between selections.

A method and apparatus such as herein described thus makes possible the division of a pulp into two or more different grades of different fiber lengths. The longest fiber portion isgenerally most valuable and maybe used for manufacture into products notably superior to those produc'ible from the original pulp. Or it may be desirable to give this valuable portion a special processing, for instance processing to produce a product high in alpha cellulose, where the original pulp is a wood pulp such as sulphite. The short fiber portion may be used 'for purposes where fiber length is of secondary importance, as in the manufacture of such papers as require an easy beating pulp. It may also be used as a raw material for the 'manufacture of cellulose derivatives. particularly when the original pulp is of high alpha cellulose content and its content of fine impurities has been removed therefrom.

While in the particular embodiments illustrated I have described the operation of selectionas performed on an aqueous pulp suspension, it should be understood that my invention comprehends selection from other mediums or carriers for cellulose fiber, both liquid and gaseous. Thus, cellulose fibers such as those of cotton or wood pulp may be suspended in a current. of air or other gasand carried or blown into grille arrangements or selectors such as hereinbefore described, to effect a selection of the portion consisting mainly of long fibers. Fiber recovery may also be effected with an air blast operating in much the same way as the water sprays already mentioned. Hence, by the expressions pulp or pulp. suspension as used in the appended claims, I mean'fiber suspended in water, air, or other liquid or avmg thus described certain embodithriIpulp is effected.

- 2. A method of selecting long fibers from cellulose pulp, which comprises causing relative movement between such pulp comparatively dilute suspension and edge-presenting members so as to cause long, relatively flexible fibers to be picked up on the edges of said members, and washing and recovering such fibers from said members.

3. A method of selecting long fibers from cellulose pulp. which comprises moving edge-presenting members through such pulp, in comparatively dilute suspension, thereby picking up long, relatively flexible, fibers on the edges of said members and removing and recovering such long fibers from said members. i

4. A method of selecting long fibers from cellulose pulp, which comprises moving edge-presenting members through such pulp in comparatively dilute suspension, thereby folding the long fibers over said members,

and washing and recovering the fibers from such members.

5. A method of selecting long fibers from cellulose pulp, which comprises movingv edge-presenting members through a pulp suspension flowing in the same direction but at lower speed than said members, and removing and recovering the pulp picked up by said members.

6. A method which comprises moving edge-presenting members through pulp thereby picking up long, relatively flexible fibers on the edges of said members, washing and recovering such long fibers from said members, and removing fine impurities from the rest of the pulp.

7. A method which comprises passing an endless succession of grilles capable of picking up long cellulose fibers through cellulose pulp, and removing and recovering the fibers picked up thereby when such grilles emerge from the pulp.

8. A method which comprises passing an endless succession of, grilles capable of picking up long cellulose fibers through a cellulose pulp suspension moving at lower speed in the same direction as the grilles, and Washing and recovering picked-up fiber from the grilles after they have emerged from the pulp.

, Apparatus of the class described, comrising edge-presenting members capable of icking u long, relatively flexible fibers rom cellu ose pulp, and means for moving said members into and out of the pulp.

10. Apparatus of the class'described, comprising edge-presenting members capable of picking up long fibers from cellulose pulp, means for moving said members into and out of the pulp, and means for removing the picked-up fibers from said members.

11. Apparatus of the class described, comprising a plurality of edge-presenting members capable of picking up long fibers from cellulose pulp, means for moving said members into and out of the pulp, and means for spraying water against said members after emergence from the pulp, to remove the fibers therefrom.

12. Apparatus of the class described, comprising edge-presenting members capable of picking up long fibers from cellulose pulp, means for movin said members into and out of pulp, means or spraying Water against said members to'wash the long fibers therefrom after they have emerged from said pulp, and means for recovering the fibers washed from said members.

13. In combination, a vat for containing cellulose pulp, an endless succession ofedgepresenting members capable of picking up longfibers from such pulp, and means for causing the movement of said members through such pulp.

14. In combination, a vat for containingcellulose pulp, an endless carrier in said vat, a succession of grilles mounted on said carrier and capableiof picking up long fibers from such pulp, means for causing the movement of said carrier through such pulp, and means for removing the picked-up fibers from said grilles.

15. In combinatiom'a vat for containing cellulosepulp, an endless carrier partially submerged in such pulp, a succession of grilles mounted on said carrier and capable of picking up 'long fibers when moved through such pulp, means for causing the movement of said carrier through such pulp, and means for washing and recovering the picked-up fibers from said grilles.

16. Apparatus of the class described, com- A prising a shaft, spiders arranged in spaced U relation on said shaft, a pluralit relation on said shaft, and a plurality of grilles. secured around the eriphery of said spiders and capable of picking up long fibers from cellulose pulp.

17. Apparatus of the class described, comprising a shaft, spiders arranged in spaced of grilles secured around the periphery 0 said shaft, and capable of picking up long fibers from prising a shaft, s aced' spiders on said shaft rods extending rom spider to. spider, an sharp-edge blades arranged in spaced relation on said rods.

19. A method which comprises causing relative motion between an unbeaten cellulose pulp suspension and edge-presenting memover said members, and removing and recovering such long fibers from said members.

20. A method which comprises causing relative motion between a cellulose pulp suspension of about 0.2% to 0.3% and edge-presentingmembers so as to cause long,relatively "flexible fibers to be picked up by such members, and removing'and recovering such long fibers from said members.

21. A method which comprises causing relative motion between a cellulose pulp suspension of about 0.2% to-0.3% and edge-presenting members so'as to cause long, relatively'flexible fibers to be picked up by such members, and washing and recovering such fibers from said members.

22. In combination, .a channel through which a stream of cellulose pulp suspension may continuously flow, a rotor, an endless 'succession of edge-presenting members carried by said rotor and progressively dipping into and issuing from said suspension uring the operation of said rotor, and means for removing and recovering the fibers picked up from said suspension by said members as they progressively issue from the suspension. 7

23. In combination, a channel through which a stream of cellulose pulp suspension may continuously flow, a rotor,'an endless bers so as to cause a folding of the long fibers In testimony whereof I have afiixed my signature. ROBERT A. WEBBER.

pulp, means for rotating said shaft, and

means for .washing and recovering the picked-up fiber from the grilles.

18. Apparatus of the class described, com- 

